I want to use one/two deep cycle batteries for a power source when camping, emergencies, etc. I would like to use a solar panel with a trickle charge to have them 100% til needed. Anyone have knowledge of a kit, plans for just a good solar charger? I’d prefer to have one that i could screw and bolt to the battery terminals vs. the typical "clamps".
You can go to a solar shop and get some of what is required, either locally or off the web. You need a 36 cell (12V) solar panel, the bigger the better, a regulator (so it stops charging when the batteries are full), some cable rated to suit the current from the panel, and clamps for the battery. You can get clamps like a car battery has, with wing nuts. A bought regulator may be cheaper. Get a basic one if there are various types, current rated at least what your panel is.
If you go to the first link, there is a circuit for a satisfactory regulator up to 10A. CLick on it for a better image that you can print out. You can make it more current by paralleling the output FET with another. Note that Q3 the power switch is a P channel FET, not the more common N channel. The op amps are a CMOS rail to rail type, with no diode clamps on the inputs. They are +/- 8V rated (so 16V maximum). The panel can put out 22V when the battery is disconnected, so that is why they have a regulator. It is also the reference voltage. The transorb can be replaced by a 100nF capacitor. The thermistor can be replaced by a resistor of the same value. It is to adjust the charge voltage for temperature when using gel type (SLA) batteries. No need for a deep cycle or car battery (flooded electrolyte). It is a good idea to put a "gate stopper" resistor in series with PFET gates to make sure it cannot oscillate – 100 ohms. Q2 is a preregulator so the 7805 is safe with a 24V panel, not needed for 12V. S1B is not used (see parts list). The equalise switch is to give an overcharge, not really needed.
How it works.
It switches on until the battery voltage is the float voltage (13.85V or slightly higher), then off till the battery is about a volt lower, then back on. I have used a similar regulator on 12 different stations for about 20 years, so I can vouch for it as being satisfactory. No need to load panels down and so on, just disconnect them.
Other stuff
If you put a solar panel on the grass or ground, it will quickly get hot, over 60C, and stop charging. The output voltage has a negative temperature coefficient so the voltage is too low to charge. It needs air circulation.
D1 is a shottky diode for its lower voltage drop. A 36 cell panel has enough voltage to charge a 12V battery at 60C with one diode drop in series. Most panels have a diode in the terminal strip. If that is removed you could use an ordinary diode (20 or 30 amps), but the shottky type is better.
If the PFET is a TO220 pack it probably doesn’t need a heatsink, or just a small one, say 6 Watts..
It is useful to have an ammeter in series with the battery. A ten amp one is fine. Helps line up the panel if nothing else.
The second link has a lot of good links, and is one example of a solar regulator.
The lines drawn heavier on the circuit should be 10A or 20A wire.
Where do you get the less common parts? Farnell, Radio Spares, Digikey.